A Possible Role for Cholinergic Neurons of the Basal Forebrain and Pontomesencephalon in Consciousness

Woolf, Nancy J.

doi:10.1006/ccog.1997.0319

Cited by 49 publications

(24 citation statements)

References 96 publications

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“…A possible underlying physical substrate for determining the collective of dendrite segments that will engage in this process at any one time might be related to the infrastructure of the microtubules in those dendrite segments. Coherence might be expected to occur in sets of dendrite segments sharing a similar microtubular infrastructure, for example, the same speci®c spacing intervals between MAP-2 binding sites to microtubules (Woolf, 1997). The chemical cascades described in the present paper would be capable of simultaneously constructing dendrite segments in multiple cholinoceptive cells, and it is conceivable that dendrites made at the same time may have similar infrastructures.…”

Section: The Structure Of Information Storagementioning

confidence: 85%

“…Dierent brain regions were evaluated in the two studies that might account for the dierent outcomes, however. The current notion of an associable representation has many features in common with a moment of consciousness (see Woolf, 1997). In this regard, the quantum coherence theory of microtubules may be relevant.…”

Section: The Structure Of Information Storagementioning

confidence: 99%

“…Cholinergic aerents might trigger microtubular coherence and self-collapse via muscarinic aects on MAP-2 phosphorylation (Woolf, 1997). This is possible, because the position of MAP-2 binding sites to microtubules aects the timing of coherence and self-collapse (see Hamero and Penrose, 1995) and phosphorylation of MAP-2 decreases binding with microtubules (Hoshi et al, 1992;Stofko-Hahn et al, 1992;Ainsztein and Purich, 1994;Diez-Guerra and Avila, 1995).…”

Section: The Structure Of Information Storagementioning

confidence: 99%

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A structural basis for memory storage in mammals

Woolf

1998

Progress in Neurobiology

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AbstractÐIt is proposed that altered dendrite length and de novo formation of new dendrite branches in cholinoceptive cells are responsible for long-term memory storage, a process enabled by the degradation of microtubule-associated protein-2. These memories are encoded as modality-speci®c associable representations. Accordingly, associable representations are con®ned to cytoarchitectonic modules of the cerebral cortex, hippocampus, and amygdala. The proposed sequence of events leading to long-term storage in cholinoceptive dendrites begins with changes in neuronal activity, then in neurotrophin release, followed by enhanced acetylcholine release, muscarinic response, calcium in¯ux, degradation of microtubule-associated protein-2, and ®nally new dendrite structure. Hypothetically, each associable representation consists of altered dendrite segments from approximately 5000±15 000 cholinoceptive cells contained within one or a few module(s). Simultaneous restructuring during consolidation of long-term memory is hypothesized to result in a similar infrastructure among dendrite sets, facilitating co-activation of those dendrite sets by neurotransmitters such as acetylcholine, and conceivably enabling high energy interactions between those dendrites by phenomena such as quantum optical coherence. Based on the speci®c architecture proposed, it is estimated that the human telencephalon contains enough dendrites to encode 50 million associable representations in a lifetime, or put another way, to encode one new associable representation each minute. The implications that this proposal has regarding treatments for Alzheimer's disease are also discussed. #

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Section: The Structure Of Information Storagementioning

confidence: 85%

Section: The Structure Of Information Storagementioning

confidence: 99%

Section: The Structure Of Information Storagementioning

confidence: 99%

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A structural basis for memory storage in mammals

Woolf

1998

Progress in Neurobiology

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“…These models which extend earlier formal models of delayed-response and card-sorting tasks and of the Tower of London test (Dehaene & Changeux 1989, 1997 offer, in particular, neuronal implementations of Baars (1998) psychological global workspace. The proposed architectures separate, in a first minimal description (see also Norman & Shallice 1980), two distinct computational spaces, each characterized by particular patterns of connections.…”

Section: Modelling Consciousness: the Neuronal Workpace Hypothesismentioning

confidence: 62%

The Ferrier Lecture 1998 The molecular biology of consciousness investigated with genetically modified mice

Changeux

2006

Phil. Trans. R. Soc. B

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The question is raised of the relevance of experimental work with the mouse and some of its genetically modified individuals in the study of consciousness. Even if this species does not go far beyond the level of 'minimal consciousness', it may be a useful animal model to examine the elementary building blocks of consciousness using the methods of molecular biology jointly with investigations at the physiological and behavioural levels. These building blocks which are anticipated to be universally shared by higher organisms (from birds to humans) may include: (i) the access to multiple states of vigilance, like wakefulness, sleep, general anaesthesia, etc.; (ii) the capacity for global integration of several sensory and cognitive functions, together with behavioural flexibility resulting in what is referred to as exploratory behaviour, and possibly a minimal form of intentionality. In addition, the contribution of defined neuronal nicotinic receptors species to some of these processes is demonstrated and the data discussed within the framework of recent neurocomputational models for access to consciousness.

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“…The GPCRs activation leads to slow biochemical organization of the neuron, while the ion channel activity leads to fast electric activity considered to correlate with conscious experience. Woolf (1997Woolf ( , 1999 as well as Woolf & Hameroff (2001) suggested that the link between the electric encoded information and the cytoskeleton does not require special explanation but indeed the information is trasferred with the G-protein coupled biochemical cascades inducted by the neurotransmitters (acetylcholine, glutamate, serotonin) that activate phosphoinositide-specific phospholipase C (PI-PLC), PKC and Ca 2+ /calmodulin activated kinase (CaMK II), which phosphorylate MAP2 molecules in dendrites that detach from microtubules. Even if we extend the model including the biochemical processes taking part in axons, the Woolf-Hameroff suggestion artificially neglects the role of the fast electric activity of the neurons in conscious processes and insists on the slow biochemical changes that once started have prolonged action (after-effects) and cannot be reversed so fast.…”

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confidence: 99%

Consciousness Operates Beyond the Timescale for Discerning Time Intervals: Implications for Q-mind Theories and Analysis of Quantum Decoherence in Brain

Georgiev¹

2007

Neuroquantology

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This paper presents in details how the subjective time is constructed by the brain cortex via reading packets of information called "time labels", produced by the right basal ganglia that act as brain timekeeper. Psychophysiological experiments performed have measured the subjective "time quanta" to be 40 ms and show that consciousness operates beyond that scale -an important result having profound implications for the Q-mind theory. Although in most current mainstream biophysics research on cognitive processes, the brain is modelled as a neural network obeying classical physics, Penrose (1989Penrose ( , 1997 and others have argued that quantum mechanics may play an essential role, and that successful brain simulations can only be performed with a quantum computer. Tegmark (2000) showed that make-or-break issue for the quantum models of mind is whether the relevant degrees of freedom of the brain can be sufficiently isolated to retain their quantum coherence and tried to settle the issue with detailed calculations of the relevant decoherence rates. He concluded that the mind is classical rather than quantum system, however his reasoning is based on biological inconsistency. Here we present detailed exposition of molecular neurobiology and define the dynamical timescale of cognitive processes linked to consciousness to be 10-15 picoseconds showing that macroscopic quantum coherent phenomena in brain are not ruled out, and even may provide insight in understanding life, information and consciousness.Key Words: quantum system, decoherence, Q-mind models, time perception, time agnosia, basal gamglia, signal transduction, G-protein coupled receptors, ion channels, cytoskeleton, tubulin, tubulin tails NeuroQuantology 2004; 2: 122-145 The brain cortex hosts our mindThe brain cortex is the main residence of consciousness. All sensory stimuli are realized only when they reach the brain cortex and not before that! Nieuwenhuys (1994) outlines the origin and evolutionary development of the neocortex. A cortical formation is lacking in amphibians, but a simple three-layered cortex is present throughout the pallium of reptiles. In mammals, two three-layered cortical structures, i.e. the prepiriform cortex and the hippocampus, are separated from each other by a six-layered neocortex. Still small in marsupials and insectivores, this new structure attains amazing dimensions in anthropoids and cetaceans. Neocortical neurons can be allocated to one of two basic categories: pyramidal and nonpyramidal cells. The pyramidal neurons form the principal elements in neocortical circuitry, accounting for at least 70% of the total neocortical population. The evolutionary development of the pyramidal neurons can be traced from simple, "extraverted" neurons in the amphibian pallium, via pyramid-like neurons in the reptilian cortex to the fully developed neocortical elements designated by Cajal as psychic cells. Typical mammalian pyramidal neurons have the following eight features in common: (1) spiny dendrites, (2) a stout radially or...

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A Possible Role for Cholinergic Neurons of the Basal Forebrain and Pontomesencephalon in Consciousness

Cited by 49 publications

References 96 publications

A structural basis for memory storage in mammals

A structural basis for memory storage in mammals

The Ferrier Lecture 1998 The molecular biology of consciousness investigated with genetically modified mice

Consciousness Operates Beyond the Timescale for Discerning Time Intervals: Implications for Q-mind Theories and Analysis of Quantum Decoherence in Brain

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